FOXBOROUGH — While their AFC rivals got dealt serious injury blows over the weekend, the Patriots had several pieces of good news on the injury front Monday, including an impressive workout by star tight end Rob Gronkowski
in plain view of the media.

First, receiver Danny Amendola returned to the field after missing both practices last week and Thursday’s exhibition game against the Lions. It is unclear why Amendola missed practice, and whether he was still limited on Monday, but he is back in action and should be ready to go when the Patriots play the Bills in the regular-season opener Sept. 8.

“We’ve had a lot of good reps in this camp so far, we’re going to continue to work and continue to get better,” Amendola said. “I didn’t get in the NFL to practice the whole time. I’m ready for Week 1 to come around.”

Several other Patriots appear to be getting healthier, as well. Cornerback Ras-I Dowling, who has sat out the last three weeks with a mystery injury and has not played in the preseason, appeared to return to full practice Monday.

Fellow injured cornerback Alfonzo Dennard, who also has sat out the last three weeks, still was limited in practice, but did conditioning drills in full uniform. Same with defensive end Jermaine Cunningham, who worked with a trainer in his uniform after not being present at practice the last three weeks.

And most important, Gronkowski was seen doing agility drills with a trainer for the first time all training camp, and looked smooth and relatively healthy as he returns from back surgery.

Gronkowski, wearing shorts and a T-shirt, ran short sprints forward, backward, and sideways inside a group of cones, and also caught and threw passes with his trainer.

Gronkowski had surgery June 18 to repair a herniated disk, and it is unclear when he will be ready to play in the regular season. The rehab for his surgery is generally about 12 weeks, which puts a potential return date right around the season opener.

Gronkowski reportedly is unlikely to play early in the season — after facing the Bills, the Patriots’ second game is against the Jets on a short week — but he could potentially be ready to play in Week 3 against the Buccaneers on Sept. 22.

The Patriots have until 4 p.m. Saturday to decide whether or not to put Gronkowski on the physically unable to perform list. If they do, he would have to sit out the first six games.

Even if he doesn’t go on the PUP list, he could still end up sitting out several games.

NFLPA assists Hernandez

According to ESPN, the NFL Players Association officially filed a grievance on behalf of Aaron Hernandez to help the former Patriots star collect an $82,000 workout bonus.

Hernandez, awaiting trial on a first-degree murder charge and five weapons charges, was supposed to receive the money if he attended the Patriots’ offseason workouts from April to June, per his contract.

The Patriots, however, voided all of Hernandez’s future guaranteed money and are withholding the $82,000 payment because the team believes he violated NFL rules by getting arrested in connection with a murder. Hernandez and the NFLPA believe that Hernandez earned that bonus before he was arrested and he has a right to collect it.

“On behalf of all players, it is our responsibility to protect the rights in the collective bargaining agreement,” the NFLPA said in a statement. “We are not tone-deaf to what the allegations are in this case, but for the benefit of all players, there are important precedents here which we must protect.”

Hernandez currently counts $2.632 million against the salary cap this year, but if an arbitrator agrees with the Patriots, that number will decrease to $2.55 million. Hernandez will count $7.5 million against the cap next year, and then come off the books for 2015.

Roster cuts

NFL teams have to cut their rosters to 75 players by 4 p.m. Tuesday, and the Patriots made several moves Monday to get down to 77.

The team released a handful of players, most notably nine-year linebacker Niko Koutouvides, a special teams contributor the last two seasons. They also released receiver Kamar Aiken, who still could be brought back to the practice squad, cornerback LeQuan Lewis, cornerback Brandon Jones, and long snapper Mike Zupancic.

Additionally, the Patriots placed two players on the reserve/non-football injury list: rookie receiver Mark Harrison, who broke his foot in the offseason while training for the combine, and defensive tackle Armond Armstead, who had an undisclosed surgery in the first week of training camp. By rule, Harrison and Armstead cannot come off the NFI list or practice with their teammates until at least Week 6.

The team also re-signed two players: rookie cornerback Stephon Morris and defensive tackle Scott Vallone, who were previously in camp before getting cut.

After getting down to 75 players Tuesday, the Patriots have to cut down to 53 by 4 p.m. Saturday. Tim Tebow, the subject of constant speculation about whether or not he will be on the final roster, said he’s not worried about not making the team.

“I learned very early on in my career at Florida to focus on what I can control, and the things I can’t control I’m not going to spend time worrying about,” he said. “But I can control my attitude, my effort, and my focus every single day, and those are the things I’m going to worry about.”

Dennard hearing postponed

Dennard’s hearing for a potential probation violation, originally set for today in Lincoln, Neb., has been pushed back to Sept. 6, according to the Lincoln Journal-Star. Dennard was arrested in July on suspicion of DUI, potentially a violation of his probation. Dennard was found guilty in April of assaulting a police officer in 2012.